The present invention relates to a broadcast receiver for digital television broadcasting or the like that enables a user to select a desired channel quickly and easily.
In recent years, digital television broadcasting such as BS (Broadcasting Satellite) digital television broadcasting or CS (Communications Satellite) digital television broadcasting has been transmitted and spreading rapidly due to the advancement of technology. In the digital television broadcasting, broadcasting stations transmit signals on a plurality of channels encoded using digital compression technology in a state of time division multiplex in a frequency band. In other words, television broadcasting signals on a plurality of channels are transmitted in a multiplex system in a frequency band. Also, the multiplex digital broadcasting signals are provided with channel information signals which are needed to reconstruct signals on a user-selected channel from the compressed multiplex signals. The channel information signals are added to the digital broadcasting signals every a few seconds so as to be transmitted together with the digital broadcasting signals.
On the other hand, at the time of reception of a channel selection command from a user, the broadcast receiver first receives digital broadcasting signals in a frequency band corresponding to the user-selected channel and extracts channel information signals contained in the received signals. Next, the broadcast receiver extracts separately signals on the user-selected channel from the received digital broadcasting signals based on the extracted channel information signals. Further, the broadcast receiver reconstructs the separately extracted signals into the state before compressed, thus reproducing the broadcasting signals on the user-selected channel. Therefore, it takes the broadcast receiver about 5 to 10 seconds to reproduce the broadcasting signals on the corresponding channel from the received digital broadcasting signals although the broadcast receiver starts the channel selection as soon as receiving the channel selection command. This causes the broadcast receiver to display a picture of no signals with no image on the display device during the period.
Moreover, a time zone for television broadcasting depends on the channel. Sometimes there is television broadcasting on a channel in a certain time zone, when there is no television broadcasting on other channels. When there is no broadcasting on the user-selected channel, the broadcast receiver fails to obtain the broadcasting signals, thus continuing to display the picture of no signals with no image on the display device.
There have been conventionally broadcast receivers which are arranged to display, during a channel selection, a message that the channel is being selected on the display device so as to inform a user whether the channel selection is being performed or there is no broadcasting on the channel. Such a receiver displays the message that the channel is being selected while performing the channel selection. As a result of the channel selection, if a television broadcast is found on the channel, the receiver erases the message and displays the image of the television broadcast, otherwise, the receiver displays a picture of no signals with no image after erasing the message.
Also, there have been channel search devices for television receivers known that select in order each of several channels which have been selected in the past and that cause multiple images of those channels to be displayed when a user operates channel search means to start a channel search (e.g., Japanese Patent Laid-open Publication No. 8-335857). Further, there have been known digital broadcast receivers that search for (select in order) and display programs on channels in order from the most frequently selected channel in the time zone when a user operates a remote control unit to provide a program search command (e.g., Japanese Patent Laid-open Publication No. 11-220675).
However, the above mentioned conventional broadcast receivers simply display the message that the channel is being selected for about 5 to 10 seconds from the reception of the channel selection command from a user until the receivers complete the selecting operation to display the image of the television broadcast. That is, during the period, the user can obtain no information for ascertaining whether or not the selected channel is the same channel as he or she desires to view. Once the user provides the channel selection command, he or she only waits for the image of the television broadcast to be displayed so as to ascertain whether or not the selected channel is his or her desired channel.
Hence, even if the user-selected channel is not the desired channel, the user must wait till the image of the broadcast is displayed so as to confirm the contents and then select another channel. That is, once providing a channel selection command, the user must wait for about 5 to 10 seconds to confirm the broadcast contents on the channel, and as a result, if the displayed image is not that of the desired program, the user must provide another channel selection command and further wait for about 5 to 10 seconds. As described above, the conventional broadcast receivers do not permit a user to confirm the contents of program during selecting a channel and take time to select the desired channel.
Neither of the disclosures in the above mentioned prior arts, Japanese Patent Laid-open Publication Nos. 8-335857 and 11-220675, are designed to solve the above mentioned problems in during channel selections.